RF Electronics Chapter 7: RF Filters Page 264
2022, C. J. Kikkert, James Cook University, ISBN 978-0-6486803-9-0.
AWR DE files for figures 7.88 to 7.94, on a modern laptop, takes about 9 minutes using
a 1 mm cell size, 25 minutes using a 0.1 mm cell size and more than 5 days using a
0.01 mm cell size. Before starting an EM simulation, make sure that all the elements in
the layout are snapped together. The first time the simulation is run, the EM structures
corresponding to the STACKUP element are created. Check that there are no errors,
which could affect the accuracy of the simulation. After the first simulation, right click
on the enclosures in the EM Structures and ensure that the materials are defined correctly
and that the layers are set up correctly, if not correct those in the STACKUP element.
Figure 7.89. Hairpin filter circuit with EM control elements and shielding ring added.
The Cadence AWR DE project file for the comparison between the circuit and EM
simulation of the hairpin filter, as presented in figures 7.88 - 7.94 has 5 circuits in it. The
numbers in the labels in figures 7.94 and 7.95 correspond to the numbers for the circuits
in the following descriptions. The first circuit (1_Hairpin Circuit) is the hairpin circuit
schematic used to produce figure 7.83, including the grounded ring, which surrounds the
PCB, made using the MCFIL element for the coupling of the resonators. The second
circuit (2_Hairpin EM) is an EM simulation of the filter circuit only, without the PCB
border.
The third circuit (3_Hairpin EM PCBRing) is the same as the first circuit, but with the
grounded PCB border ring made up from transmission lines with vias spaced
approximately 5 mm apart, added, as shown in figure 7.89. The EM simulation of
RF Electronics: Design and Simulation
264 www.cadence.com/go/awr
